This invention relates generally to fluid control valves provided with positive and negative load compensation.
In more particular aspects this invention relates to direction and flow control valves capable of proportionally controlling a number of loads under positive and negative load conditions.
In still more particular aspects this invention relates to pressure compensated direction and flow control valves, the positive and negative load compensators of which are controlled by a signal amplifying pilot valve stage.
Closed center fluid control valves, pressure compensated for control of positive and negative loads, are desirable for a number of reasons. They permit load control with reduced power losses and therefore increased system efficiency. They also permit simultaneous proportional control of multiple positive and negative loads. Such fluid control valves are shown in my U.S. Pat. No. 4,180,098, issued Dec. 5, 1979 and also in my U.S. Pat. No. 4,222,409, issued Sept. 16, 1980. However, the valves of those patents, although capable of proportional control of positive and negative loads, use for such control the energy directly transmitted through the load pressure sensing ports, which not only attenuate the control signal, but limit the response of the control.